Fig. 1

Axial abdominal magnetic resonance imaging (MRI) (a-e) and computer tomography (CT) (f) scan shows a right retroperitoneal mass with similar signal intensity to subcutaneous fat on T2-(a) and T1-(b) weighted images as well as on the CT scan. There is no diffusion restriction on the diffusion weighted images (c) and no significant contrast enhancement (e, axial T1-weighted fat suppressed image after intravenous contrast administration). The mass shows a capsule without local infiltration, but cranial displacement of the right kidney with signs of congestion (d, coronal fat-saturated T2 –weighted MRI), which gradually resolved after resection (not shown)